Answer:
4 stations
Step-by-step explanation:
If we need to be at least 98% certain that an enemy plane flying over will be detected by at least one station, we must ensure that there is at most a 2% chance that no radar stations detect the plane.
The probability that a single radar station does not detect the plane is 0.35.
For n radar stations:
Rounding up to the next whole station, at least 4 stations are needed.
Given:
To find:
The exact value of cos 15°.
Solution:
Using half-angle identity:
Using the trigonometric identity:
Let us first solve the fraction in the numerator.
Using fraction rule:
Apply radical rule:
Using :
